jill biden, visiting that embassy this morning to officially sign the book of condolences for nelson mandela. vice president biden was received at the embassy by south africa's ambassador to the u.s. mr. biden said at the meeting that nelson mandela was "the most remarkable man i ever met in my whole career." a few hours before the vice president's trip to the embassy, president obama and first lady michelle obama boarded "air force one" to start the long, 16-hour flight to south africa, where they will attend the memorial service for nelson mandela that will be held tomorrow morning. as we speak, world leaders from every corner of the globe are on their way to south africa for that memorial service and for the funeral and other events that are going to take place there over the next few days. the american delegation to south africa includes not only president obama and the first lady, but also three former presidents, george w. bush will be there and president clinton and jimmy carter. this appears to be on the second time in u.s. history that that many presidents, four living presi